Aluminum panels

ABSTRACT

An aluminum panel comprises an upper surface and a lower surface and the upper surface comprises at least one recessed area. The panel has a reduced thickness in the at least one recessed area. Both the upper surface of the panel and the at least one recessed area are provided with an aluminum oxide coating and the aluminum oxide coating of the at least one recessed area includes at least one colored dye. A method for producing an aluminum panel is also provided.

CROSS REFERENCE TO RELATED APPLICATION

This applicant claims the foreign priority benefit of BritishApplication No. 1702213.8 filed Feb. 10, 2017 for “Aluminium Panels” byC. Edge, which is incorporated by herein by reference.

TECHNICAL FIELD

The present disclosure relates to panels made from anodized aluminum andfrom anodized aluminum alloys and a method for producing such panels,and in particular to panels including a recessed design.

BACKGROUND

Aluminum signs or nameplates are typically made from anodized aluminumpanels.

Anodizing is an electrochemical process which provides the surface of ametal, such as aluminum, with an oxide coating. This anodized coating isporous and can absorb dyes to provide the panel with a colored layer.The anodized coating must then be sealed using a sealing process whichseals the pores in the coating. Anodizing increases corrosion and wearresistance of the panel and the anodized coating is non-conductive ofelectricity.

Sulphuric acid is commonly used in the preparation of anodized aluminum,producing coatings of moderate thickness, for example 1.8 μm to 25 μmthick. These coatings are known as type II coatings.

Different sealing processes are commonly used, including hot watersealing where the panel is immersed in boiling de-ionized water for acertain amount of time, and cold sealing methods, where for example thepanel may be immersed in a solution of a nickel salt, such as nickelfluoride.

Pre-anodized aluminum sheets are often used in making signs. Designs canbe engraved or etched into the anodized panels and paint can be added tothe etched or engraved areas. However, since the paint is applied to themetal surface it is less durable than dyes encapsulated within theanodic layer and also vulnerable to both wear and damage and degradationfrom solvents, pollutants or the environment.

Anoprinting is an alternative known method of printing onto aluminumpanels to make signage. This process involves printing onto a freshlyanodized, unsealed, porous surface, allowing the dyes to soak into thesurface. After the color has been applied the anodized coating is sealedto trap the dye inside the anodized surface layer. In this process thereis no etching and/or engraving so the surface of the signs is smooth andwhen a smooth surface is contaminated with dirt or soot it can bedifficult to read. With signage of this type there is also no option tomake the surface of the signs tactile and it can be difficult to readsuch signage from certain angles or in certain light conditions sincethe reflection from the surface is uniformly smooth. In addition, if theprinted image becomes bleached for example through exposure to heat orlight the image will be reduced in intensity or lost entirely. This typeof signage is also unsuitable for use on a floor as the smooth surfaceis likely to provide a slip hazard, particularly when wet.

It would therefore be desirable to provide an improved aluminum panel.

SUMMARY

According to an aspect of the present disclosure, there is provided analuminum panel or an aluminum alloy panel comprising an upper surfaceand a lower surface, the upper surface comprising at least one recessedarea, the panel having a reduced thickness in the at least one recessedarea, wherein both the upper surface of the panel and the at least onerecessed area are provided with an aluminum oxide coating, and whereinthe aluminum oxide coating of the at least one recessed area includes atleast one colored dye.

The depth of the recessed area should be sufficient to be discernible bysight or touch, preferably at least 0.1 mm relative to the upper surfaceof the panel.

Preferably the aluminum oxide coating is obtained by electrolyticanodizing treatment. More preferably the electrolytic anodizingtreatment is a sulphuric acid electrolytic anodizing treatment.

The aluminum oxide coating of the at least one recessed area may beunsealed. Alternatively, the aluminum oxide coating of the at least onerecessed area may be sealed. Anodized aluminum oxide coatings arepreferably sealed using a standard sealing process selected from thegroup comprising: hot water sealing, steam sealing, nickel salt coldsealing, chromate sealing and dichromate sealing processes.

The aluminum oxide coating of the recessed area may include more thanone dye. The aluminum oxide coating of the upper surface of the panelmay include at least one dye. The aluminum oxide coating of both theupper surface of the panel and the aluminum oxide coating of therecessed area may each include at least one dye. The dye included in thealuminum oxide coating of the upper surface of the panel may be adifferent color to the dye included in the aluminum oxide coating of therecessed area.

The aluminum panel may be selected form the group comprising: labels,nameplates, signs, badges, and flooring.

According to a further aspect of the present disclosure there isprovided a method for producing an aluminum panel comprising the stepsof:

taking an aluminum panel, the panel comprising an upper surface and alower surface, the upper surface having an anodized coating, andremoving part of the aluminum oxide coating and a proportion of theunderlying aluminum to create a recessed area on the panel; and

connecting the panel to a power supply and anodizing the exposedaluminum parts of the recessed area of the panel such that the recessedarea is provided with an aluminum oxide coating.

The method may comprise a final step of:

(c) sealing the anodized coating of the recessed area.

Preferably the aluminum oxide coating on the panel in step (a) isobtained by electrolytic anodizing treatment. More preferably, theelectrolytic anodizing treatment is a sulphuric acid electrolyticanodizing treatment.

The method may include an additional step of applying at least onecolored dye to the panel after step (b) and before step (c).

Preferably, the recessed area created in step (a) has a depth of atleast 0.1 mm relative to the upper surface of the panel.

Step (a) may be a two-step process, and comprises the steps of firstremoving the anodized coating, and the subsequently removing theunderlying aluminum. Each step of the two-step process may use adifferent removal process.

In step (a) the anodized coating may be removed by a process selectedfrom the group comprising: chemical etching, engraving, laser engravingand sand blasting.

In step (a) the underlying aluminum may be removed by a process selectedfrom the group comprising: chemical etching, engraving, laser engravingand sand blasting.

Preferably, in step (c) the anodized coating is sealed using a standardsealing process selected from the group comprising: hot water sealing,steam sealing, nickel salt cold sealing, chromate sealing and dichromatesealing processes. Where the sealing process is a hot water sealingprocess and the anodized coating is sealed by immersion in hot water,preferably water at a temperature of between 96 and 100° C., for aperiod of at least 20 minutes.

The aluminum panel used in the method may be selected form the groupcomprising: labels, nameplates, signs, badges, and flooring.

The term aluminum panel includes panels made from aluminum or alloys ofaluminum.

BRIEF DESCRIPTION OF THE DRAWINGS

In the Drawings, which illustrate preferred embodiments of the presentdisclosure:

FIG. 1a is a perspective view of an aluminum panel with an etchingstencil applied;

FIG. 1b is a cross section of the panel of FIG. 1a , through the lineX-X;

FIG. 2 is the cross section of FIG. 1b after a first etching process;

FIG. 3 is the cross section of FIG. 1b after a second etching process;

FIG. 4 illustrates the cross section of FIG. 1b after re-anodizing theetched areas of the panel;

FIG. 5 illustrates the panel after immersion in a dye solution;

FIG. 6a illustrates a cross section through the panel after the etchingstencil has been removed; and

FIG. 6b illustrates a perspective view of the panel of FIG. 1a aftertreatment with the method of the present disclosure.

DETAILED DESCRIPTION

FIG. 1a illustrates a panel of anodized aluminum 1. A cut-vinyl etchingstencil 3 has been applied to the anodized surface coating, leaving anarea 4 of the surface exposed.

FIG. 1b illustrates the cross-section taken along the line X-X. It canbe seen in FIG. 1b that the aluminum panel 1 has an anodized coating 2at its upper surface. The anodized coating 2 is a layer of aluminumoxide formed during an electrolytic process which has been subsequentlysealed using a standard sealing process. The anodized coating 2 may havebeen immersed in a dye solution prior to sealing, so may be colored.

The anodized coating 2 is removed from the exposed area 4 by applying anetching solution. FIG. 2 shows the anodized coating removed in the area4 exposed by the stencil 3, exposing the underlying aluminum metal 5.

The panel 1 is then further etched or engraved to increase the depth ofthe image area 4 to form a recessed area on the panel 1, as shown inFIG. 3. Any suitable etching or engraving method which removes materialto produce a recessed area may be used.

The panel 1 is then connected to a power supply and the exposed aluminumsurface 5 is re-anodized using a standard anodizing method, to producean anodized coating 6, as shown in FIG. 4, typically of around 25 μmthickness. Since the original anodized coating 2 does not conductelectricity it is unaffected by this second anodizing step.

At this stage, the freshly anodized coating 6 is porous and may be dyedby immersing in a dye solution, resulting in a colored anodized coating6′ as shown in FIG. 5. Since only the freshly anodized coating 6 isporous it is only this part which absorbs the dye, meaning that therecessed parts of the panel may be dyed a different color to theoriginal panel. The panel 1 is then sealed using standard sealingmethods known in the art, such as hot water sealing or cold sealingmethods using Nickel salts for example.

Lastly, as shown in FIGS. 6a and 6b , the stencil 3 is removed to reveala recessed area 4 which has been colored a different color to originalanodized coating 2.

The application of dye is an optional step and the anodized coating maybe sealed without dyeing to produce a transparent layer.

The following example exemplifies the method of the present disclosure:

Example 1

A piece of anodized aluminum plate with an anodized coating of thickness25 μm had a simple cut-vinyl etching stencil applied to the anodizedsurface.

The anodized coating from the area exposed by the stencil was thenremoved by etching in 5% NaOH solution at 20° C. for about 3 minutesuntil the aluminum metal surface became visible.

The panel was then rinsed in water.

Using a standard spray etching machine, the panel was then etched in 20%Ferric Chloride solution at 20° C. for 15 minutes to increase the depthof the area exposed by the stencil.

The panel was then rinsed in water.

The panel was then connected to a power supply and was anodized in atank using lead cathodes in a solution of 10% H2SO4 at 20° C. using acurrent of 0.018 A at 15 v for 50 minutes to produce an anodized coatingof thickness of approximately 25 μm.

The panel was then removed from the power supply and was rinsed inde-ionized water.

The panel was then immersed in a standard black anodizing dye solutionfor 20 minutes at 20° C. until the dye had fully colored the appliedanodized parts from step (vi).

The panel was then rinsed in water.

The panel was then immersed for 30 minutes in a standard sealing tankcontaining water at 97.5° C.

The stencil was then peeled from the surface and adhesive residueremoved using a proprietary general purpose washing solvent.

Masking, or similar techniques may be employed to enable more than onecolored dye to the panel.

Panels produced using this method include recessed detail or graphicsand are useful as labels, name plates, signs, badges, or flooring forexample. The recessed detail may help to enable improved tactilediscernment of the information or graphics. The recessed design can alsoproduce different reflective properties between the upper surface of thepanel and the recessed surface.

1. An aluminum panel comprising: an upper surface comprising at leastone recessed area; and a lower surface, wherein the panel has a reducedthickness in the at least one recessed area, wherein both the uppersurface of the panel and the at least one recessed area are providedwith an aluminum oxide coating, and wherein the aluminum oxide coatingof the at least one recessed area includes at least one colored dye. 2.An aluminum panel according to claim 1, wherein the aluminum oxidecoating of the at least one recessed area is unsealed.
 3. An aluminumpanel according to claim 1, wherein the aluminum oxide coating of the atleast one recessed area is sealed.
 4. An aluminum panel according toclaim 1, wherein a depth of the recessed area is sufficient to bediscernible by sight and/or touch.
 5. An aluminum panel according toclaim 4, wherein the depth of the recessed area is at least 0.1 mmrelative to the upper surface of the panel.
 6. An aluminum panelaccording to claim 1, wherein the aluminum oxide coating is obtained byelectrolytic anodizing treatment.
 7. An aluminum panel according toclaim 6, wherein the electrolytic anodizing treatment is a sulphuricacid electrolytic anodizing treatment.
 8. An aluminum panel according toclaim 1, wherein the aluminum oxide coating of the upper surface of thepanel includes at least one dye.
 9. An aluminum panel according to claim8, wherein the at least one dye included in the aluminum oxide coatingof the upper surface of the panel is a different color to the at leastone dye included in the aluminum oxide coating of the recessed area. 10.An aluminum panel according to claim 1 wherein the panel is selectedfrom the group consisting of: labels, nameplates, signs, badges, andflooring.
 11. A method for producing an aluminum panel comprising thesteps of: (a) taking an aluminum panel, the panel comprising an uppersurface and a lower surface, the upper surface having an aluminum oxidecoating, and removing part of the aluminum oxide coating and a portionof underlying aluminum of the panel to create a recessed area on thepanel; and (b) connecting the panel to a power supply and anodizingexposed aluminum parts of the recessed area of the panel such that therecessed area is provided with an anodized aluminum oxide coating.
 12. Amethod according to claim 11, further comprising a final step of: (c)sealing the anodized coating of the recessed area.
 13. A methodaccording to claim 12, wherein in step (c) the anodized coating issealed using a standard sealing process selected from the groupconsisting of: hot water sealing, steam sealing, nickel salt coldsealing, chromate sealing and dichromate sealing processes.
 14. A methodaccording to claim 12, wherein the sealing process is a hot watersealing process and the anodized coating is sealed by immersion in waterat a temperature of between 96 and 100° C., for a period of at least 20minutes.
 15. A method according to claim 11, wherein in step (a) thealuminum oxide coating on the panel is obtained by electrolyticanodizing treatment.
 16. A method according to claim 15, wherein theelectrolytic anodizing treatment is a sulphuric acid electrolyticanodizing treatment.
 17. A method according to claim 11, comprising anadditional step of applying at least one colored dye to the panel afterstep (b).
 18. A method according to claim 11, wherein in step (a) therecessed area of the panel has a depth of at least 0.1 mm relative tothe upper surface of the panel.
 19. A method according to claim 11,wherein step (a) is a two-step process and comprises the steps of firstremoving the aluminum oxide coating, and subsequently removing theunderlying aluminum.
 20. A method according to claim 11, wherein in step(a) the aluminum oxide coating is removed by a process selected from thegroup consisting of: chemical etching, engraving, laser engraving andsand blasting.
 21. A method according to claim 11, wherein in step (a)the underlying aluminum is removed by a process selected from the groupconsisting of: chemical etching, engraving, laser engraving and sandblasting.
 22. A method according to claim 11, wherein the aluminum panelis selected from the group consisting of: labels, nameplates, signs,badges, and flooring.